1. Field of the Invention
The present invention relates to a set of matched golf clubs of varying club-numbers having club-length, head-loft and head-weight characteristics such that the club-length decreases gradually and the head-loft and head-weight increases gradually in accordance with a gradual increase of the club-number, and more particularly, to a set of matched golf clubs of varying club-numbers in which each of the golf clubs can obtain a trajectory of flight of a ball and a distance of subsequent run thereof which are suitable for players with different swing styles.
2. Description of the Prior Art
Generally, a conventional set of iron or wood golf clubs of varying club-numbers has club-length, head-loft and head-weight characteristics by which the club-length decreases gradually or regularly and the head-loft and head-weight increases gradually or regularly, in accordance with a gradual increase of the club-number. However, the front surfaces of the club heads in a conventional set of the golf clubs are made to have the same characteristic. For example, in a conventional set of wood golf clubs, front surfaces of the club heads are generally provided with face-inserts, respectively, which are made of the same material such as ABS resin, paper fibers, aluminum alloy, titanium, fiber-reinforced plastic or the like, and outer surfaces of the face-inserts are finished to have the same characteristic. On the other hand, in a conventional set of iron golf clubs, club heads are generally made of the same material such as iron, stainless steel, fiber-reinforced plastic or the like, and front surfaces of the club heads are finished to have the same characteristic.
Generally, a trajectory of flight of a ball and a distance of subsequent run thereof are affected by the amount of back spin, an initial flying angle, and an initial flying velocity of the ball hit by the club head. Therefore, for example, in order to obtain a high trajectory of flight of a ball and a short distance of subsequent run thereof, it is necessary to increase the amount of back spin, an initial flying angle, and an initial flying velocity of the ball. In turn, in order to obtain a low trajectory of flight of a ball and a long distance of subsequent run thereof, it is necessary to increase an initial flying velocity of the ball and decrease the amount of back spin of the ball, as well as the angle at which the ball falls to the ground.
The head-loft of the golf club is an essential factor for determining the amount of back spin of a ball, trajectory of flight of a ball, and distance of subsequent run thereof and, as described above, the head-loft characteristic in the conventional set of golf clubs is determined so that the head-loft increases gradually in accordance with a gradual increase of the club-number. Therefore, when using a conventional set of golf clubs, the amount of back spin of a ball generally tends to increase in accordance with the increase of the club-number. However, in actual play, the amount of back spin of the ball is also affected by the various swing styles or personal habits of players. Therefore, the above-mentioned conventional set of the golf clubs in which front surfaces of the club heads have the same characteristic has a disadvantage in that all or some of the golf clubs in the set of the golf clubs may give too much or too little back spin to a ball, due to the various swing styles of the players.
It is possible to adjust the head-loft of each of the golf clubs so as to get a suitable amount of back spin on a ball. But, in order to provide club heads with several head-lofts under the same club-number, it is necessary to provide many different molds for club heads of the same club-number, and this results in a high manufacturing cost.